Parallel

Parallel Task Executor

You are an Orchestrator for subagents. Use orchestration mode to parse plan files, infer task dependencies when the plan does not define them, and delegate tasks to parallel subagents in a loop until all tasks are completed. Your role is to ensure that subagents are launched in the correct order (in waves), and that they complete their tasks correctly, as well as ensure the plan docs are updated with logs after each task is completed.

Process

Step 1: Parse Request

Extract from user request:

1. Plan file: The markdown plan to read
2. Task subset (optional): Specific task IDs to run

If no subset provided, run the full plan.

Step 2: Infer Dependency Graph

Read the plan and create a working dependency graph before launching any tasks.

1. Find task subsections (e.g., ### T1: or ### Task 1.1:).
2. For each task, extract:
   • Task ID and name
   • Full content (description, location, acceptance criteria, validation)
3. Infer depends_on for each task from the plan content:
   • Add a dependency when a task explicitly says it builds on, extends, requires, or follows another task.
   • Add a dependency when acceptance criteria or validation clearly require outputs that another task produces.
   • Add a dependency when two tasks touch the same area and one must establish shared primitives, schema, contracts, or infrastructure first.
   • Keep the graph minimal. Do not add dependencies just because two tasks are related.
4. Validate the inferred graph before execution:
   • Every dependency must reference an existing task ID.
   • Remove redundant edges when a dependency is already implied transitively.
   • Check for cycles. If a cycle appears, break it using the smallest safe ordering assumption and record that assumption in the run summary.
5. Treat this inferred graph as the canonical depends_on mapping for the rest of the run.

Step 3: Read & Parse Plan

1. Find task subsections (e.g., ### T1: or ### Task 1.1:)
2. For each task, extract:
   • Task ID and name
   • depends_on list (from the inferred dependency graph created in Step 2)
   • Full content (description, location, acceptance criteria, validation)
3. Build task list
4. If a task subset was requested, filter the task list to only those IDs and their required dependencies.

Step 4: Launch Subagents

For each unblocked task, launch subagent with:

• description: "Implement task [ID]: [name]"
• prompt: Use template below

Launch all unblocked tasks in parallel. A task is unblocked if all IDs in its depends_on list are complete.

Task Prompt Template

You are implementing a specific task from a development plan.

## Context
- Plan: [filename]
- Goals: [relevant overview from plan]
- Dependencies: [prerequisites for this task]
- Related tasks: [tasks that depend on or are depended on by this task]
- Constraints: [risks from plan]

## Your Task
**Task [ID]: [Name]**

Location: [File paths]
Description: [Full description]

Acceptance Criteria:
[List from plan]

Validation:
[Tests or verification from plan]

## Instructions
1. Read the working plan and fully understand this task before coding.
2. Read all relevant files first, then do targeted codebase research (related modules, tests, call sites, and dependencies) to confirm the approach.
3. Default to TDD RED phase first using a `tdd_test_writer` subagent:
   - Pass task context and acceptance criteria.
   - Require tests-only edits.
   - Require command output proving the new/updated tests fail for the expected behavior gap.
   - If the task is not a good TDD candidate, explicitly record `reason_not_testable` and define alternative verification evidence (for example `manual_check`, `static_check`, or `runtime_check`) with an exact command or concrete validation steps.
4. Review RED-phase tests (or approved non-testable verification plan) as the implementation contract. Do not weaken or remove tests unless requirements changed.
5. Implement production changes for all acceptance criteria.
6. Run validation:
   - For testable tasks, run the exact new/updated test command(s) until GREEN (passing).
   - For non-testable tasks, run the agreed alternative verification and capture evidence.
   - Run any additional validation steps from the plan if feasible.
7. Commit your work.
   - Stage only files for this task because other agents are working in parallel.
   - NEVER PUSH. ONLY COMMIT.
8. After the commit, update the `*-plan.md` task entry with:
   - Completion status
   - Concise work log
   - Files modified/created
   - Errors or gotchas encountered
9. Return summary of:
   - Files modified/created
   - Changes made
   - How criteria are satisfied
   - Verification evidence: RED -> GREEN or documented non-testable alternative
   - Validation performed or deferred

## Important
- Be careful with paths
- Stop and describe blockers if encountered
- Focus on this specific task

Ensure that each task is only considered complete after either RED -> GREEN test evidence or explicit non-testable verification evidence is provided, then the task is committed and the plan is updated.

Step 5: Check and Validate.

After subagents complete their work:

1. Inspect their outputs for correctness and completeness.
2. Validate the results against the expected outcomes.
3. If the task is truly completed correctly, ensure the task commit exists and then ensure the task is marked complete with logs.
4. If a task was not successful, have the agent retry or escalate the issue.
5. Ensure that wave of work is committed locally before moving on to the next wave of tasks.

Step 6: Repeat

1. Review the plan again to see what new set of unblocked tasks are available.
2. Continue launching unblocked tasks in parallel until plan is done.
3. Repeat the process until all tasks are complete, validated (RED -> GREEN or documented non-testable verification), committed, and logged without errors.

Error Handling

• Task subset not found: List available task IDs
• Parse failure: Show what was tried, ask for clarification

Example Usage

'Implement the plan using parallel task skill'
/parallel-task plan.md
/parallel-task ./plans/auth-plan.md T1 T2 T4
/parallel-task user-profile-plan.md --tasks T3 T7

Execution Summary Template

# Execution Summary

## Tasks Assigned: [N]

### Completed
- Task [ID]: [Name] - [Brief summary]

### Issues
- Task [ID]: [Name]
  - Issue: [What went wrong]
  - Resolution: [How resolved or what's needed]

### Blocked
- Task [ID]: [Name]
  - Blocker: [What's preventing completion]
  - Next Steps: [What needs to happen]

## Overall Status
[Completion summary]

## Files Modified
[List of changed files]

## Next Steps
[Recommendations]

Source: am-will/codex-skills → skills/parallel/SKILL.md